1. Field of the Invention
The present invention relates to a tongue plate stopper to be attached to a webbing of a seat belt and, more particularly, to a tongue plate stopper improved to have a high strength of attachment to the webbing and to have a reduced deformation of the webbing when it is attached to the webbing.
2. Description of the Prior Art
A seat belt system is composed, as shown in FIG. 6, of: a retractor 12 attached to a car body 10; a webbing 14 capable of being withdrawn from the retractor 12; a webbing retainer 18 attached to a center pillar 16; a tongue plate 22 by which the webbing 14 is guided to move; and a buckle (although not shown) into which the tongue plate 22 is inserted. The webbing 14 is equipped with a tongue plate stopper 24 for preventing the tongue plate 22 from sliding down when an occupant is not restrained, as shown.
The tongue plate 24 is exemplified in the prior art, which comprises a first disc having one needle projected from the center thereof and a second disc having a hole or recess for fitting the needle therein, as disclosed in Japanese Utility Model Laid-Open No. 23147/1981 or West German Utility Model No. 7531666. This tongue plate stopper is fixed to the webbing by fitting the needle in the hole or recess.
West German Utility Model No. 7531666 has also disclosed another structure, in which a first disc having a plurality of needles is fitted in a second disc by inserting the individual needles through the webbing into the second disc.
Since the weight of the tongue plate to be applied to the tongue plate stopper is wholly concentrated at the needle or needles, concentration of load occurs in the webbing wefts running crosswise below the needle or needles. As a result, the wefts are exclusively tensed to establish the "constrictions" 26 at the sides of the webbing 14, as shown in FIG. 7.
Moreover, the tongue plate stopper of the prior art is retained in the webbing by a small number of needles. Thus, there arises a problem that the strength of attachment of the tongue plate stopper to the webbing, namely, the retaining strength in the longitudinal direction of the webbing is low.